BattleTech eras

Catalyst Game Labs, the current owners of BattleTech, have divided history into six eras. The products they released are grouped in this manner. Recently newer products have included other distinct time periods by splitting the eras into sub-eras which brings the classification up to nine eras. In addition to those, four more distinct non-canon ones can be identified:

Era	Sub Era	Years	Description	Symbol
	Pre-Spaceflight	Before 1950	Earliest era referenced, when humanity only resides on its planet of origin, Terra.
	Early Spaceflight	1950 – 2005	Early solar system restricted spaceflight.
Age of War	Age of War (First Exodus)	2005 – 2242	The time of the Western Alliance, early Terran Alliance, and earliest interstellar colonies. The Outer Reaches Rebellion resulted in the Demarcation Declaration, the forced independence for most colonies.
Age of War	Age of War (Second Exodus)	2242 – 2398	Colonists on marginal worlds resettle or perish. The Terran Alliance collapses; the beginnings of the Terran Hegemony and the Great Houses of the Inner Sphere.
Age of War	Age of War	2398 – 2570	The time of the Terran Hegemony and "civilized" warfare between the Inner Sphere houses. The first BattleMech is created.
Star League	Star League	2571 – 2781	The time when the Star League reached the height of its power and was destroyed by the Amaris Coup.
Succession Wars	Early Succession Wars	2781 – 2900	The start of the Succession Wars, when the Successor States of the Great Houses vied for supremacy after the collapse of the Star League.
Succession Wars	Late Succession Wars	2901 – 3049	After years of war, many of the advances of the Star League had disappeared, becoming LosTech. Warfare between the Successor States ground down to low-level fighting.
Clan Invasion		3050 – 3061	The time between the beginning of the Clan Invasion and the Inner Sphere's victory at the Great Refusal.
Civil War		3062 – 3067	The years in the shadow of the Federated Commonwealth Civil War.
Jihad		3068 – 3080	The time when the Word of Blake unleashed its Jihad.
Dark Age	Formation of The Republic	3081 – 3130	The time from the defeat of the Blakists to the creation of The Republic of the Sphere.
Dark Age	Dark Age	3131 – 3150	The time since the collapse of the HPG network caused political chaos in The Republic of the Sphere that led to the militarization of Industrial Mechs and other civilian equipment.
IlClan	IlClan	3151 –	The once-invulnerable Republic of the Sphere lies in ruins, torn apart by the Great Houses and the Clans. As Fortress Republic collapses, the Clans race toward Terra to create a supreme authority which will rule the Inner Sphere by any means necessary.

Bibliography

• Master Unit List: Battle Value
• Strategic Operations
• The Periphery (sourcebook)
• Record Sheets: Clan Invasion